Ratchet clutch assemblies are known in the art for providing unidirectional ratchet action for rotating tools such as screwdrivers, wrenches, socket drivers and the like. Certain ratchet clutch assemblies known in the art are based on the use of a locking pawl or catch with a notched cogwheel or ratchet wheel, in order to provide unidirectional ratchet locking for driving a rotating tool bit. In such ratchet designs, the action of the pawl catching on the cogs or notches of the ratchet wheel may result in undesirable clicking or cogging of the clutch assembly when rotated in a non-locking or freewheeling direction. Further, such designs may also suffer from undesirable drag or friction in the non-locking or freewheeling direction, due to the motion of the pawl against the ratchet wheel. Such ratchet designs may further suffer from undesirable backlash or fugitive rotation in the locking direction, before the ratchet clutch locks to provide driving rotation of the tool.
A further type of ratchet clutch assembly known in the art are based on the use of bearings, such as substantially spherical and/or cylindrical roller bearings which may be used to provide ratchet locking of the clutch against rotation in one locking direction while providing for freewheeling rotation of the clutch in another non-locking direction. Some such known bearing ratchet designs may require multiple co-rotating components between the bearings and the rotational surfaces of the clutch which may be undesirably complex and/or may undesirably increase friction or drag within the clutch assembly. Further, some such roller bearing ratchet designs may require one or more separate indexing mechanisms in order to provide for indexed reversibility of the ratchet rotation direction, which may further add complexity to the rotating design of the clutch assembly. Finally, some such roller bearing clutch designs may also require an undesirable degree of backlash rotation in order to lock the clutch assembly and provide for locking ratchet rotation to drive a tool.
Accordingly, there is a need for a ratchet tool design, such as may be suitable for ratchet bit driving tool applications, that addresses some of the limitations of existing ratchet tool clutch assembly designs according to the art.